The present invention relates to the preservation of paper articles (e.g., books, manuscripts, documents) and textiles articles (e.g., paintings on canvas, clothing, etc.) through the application of an amorphous fluoropolymer by, for example, spraying, dipping or brushing the article to be preserved with a solution of the fluoropolymer.
Commonly owned and copending PCT International Application No. PCT/US98/26903 discloses coating a substrate (e.g., a metal, ceramic or composite) including the application of a fluoropolymer solution to seal pores.
The use of fluoropolymer dispersions to coat and protect paper and fabrics is known (see e.g., U.S. Pat. Nos. 4,742,140 and 5,674,961). Generally, these dispersions are comprised of particles in the neighborhood of 80 to 400 nm in diameter in an aqueous medium. The particles are not intended to fully or uniformly coat the fibers of paper or fabric. Also, because they are generally aqueous dispersions, items containing water-solution dyes would be damaged by contact with water.
WO A 92/10532 teaches fluorinating the surface of polymers by deposition of fluorocarbons from solution. WO A 97/19224 is a process for preserving paper by polymerizing polycondensates in situ. GB A 007 981 discloses lamination of paper or textile articles. U.S. Pat. No. 5,409,736 describes impregnation of paper with particles of oxides which hydrate to bases.
The present invention provides a method for strengthening a cellulosic paper or textile article, comprising the steps of (a) applying to the article a solution of an amorphous fluoropolymer in a perfluoroalkane solvent; and (b) drying the article so that the solvent is essentially removed.
The present invention also relates to a strengthened cellulosic paper or textile article comprising (i) a fibrous cellulosic paper or textile substrate and (ii) amorphous fluoropolymer interconnecting fibers of said substrate.